1. Field of the Invention
This invention relates to information collection and reporting systems for reporting real-time weather and runway condition information, and particularly to information that is obtained through the use of visual images of the sky, horizon and terrain transmitted from a distant location to a hub location wherein the images can be accessed by all interested users.
2. Description of Related Art
For convenience, the following abbreviations and acronyms are defined here:
ASOS--Automated Surface Observing System PA1 AWOS--Automated Weather Observing System PA1 Clear-Day Image--Image of a particular view which has been captured on a day free of weather obstructions to vision and is annotated with written and graphic information about objects in the image. PA1 Current Image--Image of a particular view no more than 30 minutes old PA1 FAA--Federal Aviation Administration PA1 Image--The visual product produced on a computer monitor PA1 ISP--Internet Service Provider PA1 NWS--National Weather Servicezx PA1 View--The visual extent of coverage, top to bottom and left to right of the camera which is collecting the image
Since the beginning of air travel, pilots have had to deal with the weather. Bad weather may prevent pilots from approaching and landing at airports. Today, pilots get pre-flight and in-flight weather information to help them anticipate weather conditions they may encounter along their route of flight. Some airports have navigation aids, communications facilities and weather reporting systems to assist pilots in dealing with the weather.
The situation is not as good, however, for hundreds of other airports and landing fields throughout the world. For these locations, a pilot may get a regional briefing or a pilot report at best. Often, pilots arrive at an airport only to find it is "weathered in" and the pilot cannot land. This increases risk and may result in accidents or emergencies. It also results in inefficiencies and lost revenue for commercial air carriers.
To solve this problem, many weather observation resources have been developed. A human observer is an excellent source of weather information. He may be under contract with the FAA, NWS or a third party contractor that provides information to federal agencies. However, cuts in government budgets have encouraged a move away from human observers to automated systems.
Another type of observation system is the automated weather observing system (AWOS) or automated surface observing system (ASOS), which are in use by both the FAA and the NWS. They are an excellent source of information for wind speed, wind direction, temperature, dew point and altimeter setting. They are weak in their collection of visibility and ceiling data. For example, they provide no information about sky conditions in any of the cardinal directions (north, south, west or east). While an overcast ceiling directly above the airport may discourage a pilot from attempting a flight to that location, it is completely plausible to have poor conditions directly over the airport, but clearing or completely clear conditions to the north or south. Thus, they are limited in the extent to which they provide useful information about the complete celestial dome. In addition, the sensors that determine ceiling often do not operate properly in some weather phenomenon. Low temperatures, ice fog, haze and other anomalies often cause these systems to erroneously report that conditions do not support VFR flight when in fact they do.
The second problem with these systems relates to visibility. Automated systems use an emitter and sensor in close proximity to one another (several feet) to measure reflected light scattered by the atmosphere. Algorithms use the amount of reflected light to extrapolate over a large distance and establish a measure of visibility in miles. This system is also flawed in two ways. First, it only measures local visibility at the point of the instrument. To the extent that the microclimate at the point of the instrument is applicable to the area surrounding the airport for 15 miles, it may accurately state the prevailing visibility. This is often a poor assumption. Secondly, the automated systems extrapolate over a distance of 3 feet to distances measured in miles. Variations in weather, as well as smoke, haze, blowing dust, local fog, idling engines, chimney smoke, etc. confuse the sensors and may produce a completely inaccurate representation of current conditions.
The next type of weather aid is satellite imagery. These products provide both visible spectrum and infrared images of the weather from space. While they provide excellent information about the presence of major cloud layers or the lack thereof, they provide no information about the actual conditions beneath a broken or overcast layer of clouds. Therefore, once they establish that the sky is overcast at a particular location, they cannot discern the ceiling, the type of layers, the number of layers or other information that is helpful to a VFR pilot.
Another weather aid is NEXRAD radar. Radar helps immensely in establishing the density of cloud buildups and the amount of precipitation or water vapor within the region. While they detect the presence of very bad flying conditions due to heavy precipitation, or impaired flying conditions due to light precipitation NEXRAD does not positively identify areas where the ceiling or visibility is such that it is conducive to VFR flight.